Disabling compression for IE pre SP2 with Apache mod_rewrite

Question

I am trying to replicate this fix ( http://sebduggan.com/posts/ie6-gzip-bug-solved-using-isapi-rewrite ) with Apache mod_rewrite, but with no success... Can somebody help me translate those ISAPI rules to APACHE mod_rewrite? I don't know how to 'translate' those rules...

My objective is to avoid sending compressed css and js when the user has an XP version prior to SP2, since there is a bug that prevents IE6&7 under SP1 to read the gzipped CSSs of my website BuscoUnViaje.com

The rules I am trying to 'translate' to Apache mod_rewrite:

RewriteCond %{HTTP:User-Agent} MSIE\ [56]
RewriteCond %{HTTP:User-Agent} !SV1
RewriteCond %{REQUEST_URI} \.(css|js)$
RewriteHeader Accept-Encoding: .* $1

Thanks in advance...